The proposed research will elucidate the mechanism of sperm dysfunction in the case of segregation distorter and it will undertake the examination of the SD system as it exists in nature with an eye to develop methods of population control in insects using meiotic drive. The relationship between the failure of individualization observed in some SD's and the complementation phenomenon I have discovered will be investigated cytologically by examining quantitatively the amount of individualization observed in SD's and correlating this with the position and extent of the SD chromosome on the complementation map. The mutation induction said to be caused by SD will be investigated using classical schemes for mutation detection and characterization. Natural populations will be extensively screened for SD and for suppressors of SD to determine whether suppressors are so common in populations having meiotic drive that the seeding technique of population control using meiotic drive would not be effective. Studies on SD-Y translocations in population cages will be carried out to determine the effectiveness of this control scheme and to evaluate the effect of suppressors.